Silicon-containing organoboron compounds and method for their preparation



June 16, 1964 s. PAPETTI 3,137,719

SILICON-CONTAINING QRGANOBORON COMPOUNDS AND METHOD FOR THEIR PREPARATION Filed Jan. 25, 1961 FIGURE 1 FORMULA I FORMULA II O BORON 2 CARBON V a SILICON o HYDROGEN ON CARBON (HYDROGEN ATOMS 0N BORON OMITTED FOR CLARITY) INVENTOR. STELVIO PAPETTI MM/t 10M AGENT United States Patent 3,137,719 SILICON-CONTAINING ORGANOBORON COM- POUNDS AND METHOD FOR THEIR PREPA- RATION Stelvio Papetti, Hamden, Conn., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Jan. 25, 1961, Ser. No. 84,955 16 Claims. (Cl. 260-4481) This invention relates to silicon-containing organoboron compounds and to a method for their preparation. The silicon-containing organoboron compounds are prepared by reacting an organoboron alkali metal compound of the formula:

wherein R and R are each selected from the class consisting of hydrogen and an alkyl radical containing from 1 to carbon atoms and wherein R and R are each selected from the class consisting of hydrogen, an alkali metal, an alkyl radical and an alkenyl radical, at least one of R and R being an alkali metal and the total number of carbon atoms in R and R taken together not exceeding eight, with a silane compound of the formula:

wherein R is selected from the group consisting of an alkyl radical containing 1 to 5 carbon atoms or an aryl radical containing not more than carbon atoms and wherein R is selected from the group consisting of a halogen and a haloalkyl radical containing from 1 to 5 carbon atoms, said halogen being selected from the group consisting of chlorine, bromine and iodine and n is an integer of 1 to 3, with the proviso that when R is a haloalkyl radical n is at least 2.

Organoboron alkali metal compounds useful as starting materials in the process of this invention can be prepared by reacting a material selected from the class consisting of an alkali metal alkyl and alkali metal aryl, a compound of the class RR B H (CR CR) wherein R and R are each selected from the class consisting of hydrogen and an alkyl radical containing from 1 to 5 carbon atoms, wherein R and R are each selected from the class consisting of hydrogen, an alkyl radical and an alkenyl radical, at least one of R and R being hydrogen, and the total number of carbon atoms in R and R taken together not exceeding eight. Preparation of these compounds is described in application Serial No. 809,571, filed April 28, 1959 of Ager and Heying. For example, B H [CHC(Li)] can be prepared by reacting equimolar quantities of methyl lithium with carborane [B I-I (CHCH)], in diethyl ether. Methyl lithium dissolved in diethyl ether is added to a diethyl ether solution of carborane until as indicated by a wet test gas meter suflicient methane has been produced to indicate the formation of the mono-lithium salt. In the final phase of the reaction it is sometimes necessary to heat the reaction mixture to a temperature somewhat below reflux temperature in order to accelerate the methane evolution. Evaporation of the diethyl ether from the reaction mixture leaves a residue which is B H [CHC(Li)].

Compounds of the class RR B H (CR CR) can be prepared by the reaction of decaborane or an alkylated decaborane having 1 to 2 alkyl groups containing 1 to 5 carbon atoms in each alkyl group with an acetylenic hydrocarbon containing from 2 to 10 carbon atoms in the presence of a wide variety of ethers, nitriles or amines. The preparation of these compounds is described in ap plication Serial No. 741,976, filed June 13, 1958 of Ager,

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Heying and Mangold, now abandoned. For example, B H (CHCH) can be prepared by reacting for about 12 hours at 125 C. a mixture of decaborane and tetrahydrofuran in an autoclave pressured to 100 p.s.i. with acetylene.

The preparation of decaborane is known in the art. Lower alkyl decaboranes such as monomethyldecaborane, dimethyldecaborane, mouoethyldecaborane, diethyldecaborane, monopropyldecarborane and the like, can be prepared, for example, according to the method described in Altwicker et al. application Serial No. 497,407, filed March 28, 1955, now US. Patent No. 2,999,117, granted September 5, 1961.

The novel silicon-containing organoboranes of this invention are of the class consisting of:

wherein R and R are each selected from the class consisting of hydrogen and an alkyl ralical containing 1 to 5 carbon atoms, wherein R is selected from the class consisting of hydrogen, an alkyl radical containing 1 to 8 carbon atoms and an alkenyl radical containing 1 to 8 carbon atoms, wherein R is an alkyl radical containing 1 to 5 carbon atoms, wherein X is a halogen selected from the class consisting of chlorine, bromine, and iodine, wherein R is a haloalkyl radical containing 1 to 5 carbon atoms, said halogen being selected from the group consisting of chlorine, bromine and iodine, wherein R is a bivalent saturated hydrocarbon radical containing 1 to 5 carbon atoms, wherein n is an integer from 1 to 3, m is an integer from 0 to 2, r is an intger of from 0 to 1 and the sum of m plus n is not over 3.

The solid products prepared in accordance with the method of this invention when incorporated with suitable oxidizers such as ammonium perchlorate, potassium perchlorate, sodium perchlorate, ammonium nitrate and the like, yield solid propellant suitable for rocket power plants and other jet propelled devices. Such propellants burn with high flame speeds, have high heats of combustion and are of the high specific impulse type. The solid products of this invention when incorporated with oxidizers are capable of being formed into a wide variety of grains, tablets and shapes, all with desirable mechanical and chemical properties. Propellants produced by the methods described in this application burn uniformly without disintegration when ignited by conventional means, such as a pyrotechnic type igniter, and are mechanically strong enough to withstand ordinary handling.

The ratio of the reactants can vary widely, generally being within the range of from about 0.5 to about 10 moles of silane compound per mole of organoboron compound employed and preferably in the range of from about 1 to 5 moles of silane compound per mole of organoboron alkali metal compound.

The temperature of the reaction of the organoboron alkali metal compound with the silane compound is generally maintained between C. and +70 C. and preferably at or below room temperature.

The pressure employed can be varied widely, although atmospheric pressure reactions are convenient. The reaction of the organoboron alkali metal compound with silane compound is substantially instantaneous. Slow addition of the silane compound is practiced to prevent overheating.

Silane compounds suitable as starting materials in the process of this invention include, for example, methyltrichlorosilane, dimethyldichlorosilane, triethylchlorosilane, diethyldichlorosilane, di-n-propyldichlorosilane, n-butyltrichlorosilane, diphenyldichlorosilane, triphenylchlorosilane, amyltrichlorosilane, triamylchlorosilane, phenyltrichlorosilane, tolyltrichlorosilane, trimethylchloromethylsilane, diethyl bis(chloromethyl)silane, diethyldi-nchloropropylsilane, tri-n-propylchloroethylsilane, and the corresponding bromine and iodine derivatives.

ously prepared methyl lithium ether solutionwas added to the dropping funnel and about 100 ml. of this solution was added dropwise at approximately C. to the reactor. At this point some 0.1 mole of methane as measured by ethyl ether was decanted from the reaction mixture.

In a nitrogen atmosphere 14.4 grams (0.1 mole) of carborane [B I-I (CHCH)] was dissolved in 170 ml. of dry diethyl ether in a round bottom, l-liter, three neck flask equipped with a magnetic stirrer, a gas inlet tube, a dropping funnel and a Dry Ice condenser connected to a wet test meter through a Dry Ice trap. The system was also provided with a bubble off. A quantity of the previ- The preferred alkali metal alkyl are the lithium alkyls 5 the wet test meter had been evolved from the reaction such as methyl lithium, ethyl lithium, isopropyl lithium, mixture thus indicating the reaction of the methyl lithin-propyl lithium, n-butyl lithium, sec-butyl lithium, t-buum with carborane to form the compound lithium cartyl lithium, n-amyl lithium and the like, since they are borane [B H (CHC(Li))]. The lithium carborane .soluble in inert organic solvents. Other alkali metal solution so formed (approximately 265 mls.) was transalkyls, such as sodium and potassium alkyls can, howferred to a calibrated addition funnel. ever, also be employed as can the alkali metal aryls in- B T th I l b eluding phenyl lithium. y y

The reaction can be carried out in an inert solvents In e apparatus Prevwusly descrlbed for the p p aother than the diethyl ether employed in hi ifi tlon of l1th1um carborane 1.52 grams (0.014 mole) of-tr1- amples. Such solvents include for example, dimethyl methylchlorosllane w added dropwlse atroorptemperaether, diethyl ether, methylethyl ether, diisopro yl th ture to 37 .1 ml. lithium carborane of the prevlouslypredi-n-propyl ether, ethyl-n-butyl ether, ethylene glycol d1. pared lithium carborane diethyl ether solutlon containing methyl ether, dioxane and t t h d f 2.2 grams or 0.014 mole of lithium carborane. The reac- This invention is illustrated in detail by the f ll i t1on was 1nstantaneous as evidenced by the immedlate examples which are to be considered not limitative. P P of hthlllm chlol'lde- To msm'a comPlFtlon In the example, the term i ifi gram 1 of the reaction the mixture was refluxed for an addltlonal EXAMPLE six hour period. The product was then treated with 50 I mls. cold dilute hydrochloride acid solution to decompose (A) Preparation of Li hi c bo a any unreacted lithium carborane and also to dissolve the [B H (CHC(L precipitated lithium chloride. Next the ether layer was separated from the aqueous layer and it was dried over g: fi g ggg gg g gg f it: calcium chloride for 24 hours and finally taken to dryness. A In 28 pp The residue was solved in about 100 ml. of pentane and p h 1 out in filtered. When the pentane solution was cooledto 0 C.

The Preparatlon of met Y 1 2 was gi E d 30 a first crop of crystals of the desired product was obtained a three k 500 fllilsk Gonnecte i and further cooling to Dry Ice temperature resulted in equipped wlth a magneuc sun-er a gas 1 at the crystallization of additional amount of the trimethylplrlg funn l and Water-cooled conflenser' l silylcarborane product. The total product was further being used, t e sy Was flushed wltll a stream 0 m purified by sublimation under vacuum at 90 C. yielding gen. An amount of 100 ml. of dry methyl ether and 2.8 ur th I 1 b p e um ysiycar orane grams (0.4 atom) of llthmm metal shot were placed m D the reaction flask. An amount of 28.5 grams (0.2 mole) (CH S1[CHC(B H of methyl iodide dissolve? in 9 of methyl ether was which had a melting point of 9495 C. The product added dI'OPWISe to the 'f Shot at room was subjected to chemical analysis and the following reperature. As soon as the reaction started the flask was 40 n were obtained cooled to a temperature of about 0 C. and the remainder calcd for C5H20SiBm. B, 300; C, 273; H

of the methyl iodide solution was added over a period of Found: B 298, 295; C, 280 2&0; H, 9A3, 957. minutes. Throughout the reaction, cooling of the reaction flask was necessary to slow down the reaction rate. EXAMPLES After all of the methyl iodide solution had been added, 45 A number of additional experiments were performed the reactlon mixture was allowed to warm up to room using the same apparatus and procedure described i E tempera ure and t en ea e at refl x fo O e 11 1 The ample I. Pertinent details relating to these experiments reaction mixture was filtered through glass wool and are given i bl h TABLE 1 Reactants R? Analysis of Product action Melting mi 1e Weight Weight SEQ Product Pant p Compound (grams) Compound (grams) tgue) 0) gigg Found w tt[ 6.2 (cnmslol 10-7 0 3)2 l0 l0 ]z 196.5 B 62.2 62. 5-628 021.0 21.5-21.2 III B10Hm[CHC(Ll)] 0. 75 (CGH5)3SlCl 1.4 0-35 (otnmsfloncm n n 165.167 2f? $1331? 0 59.9 61.0-62.3,

64.6 H 6.5 6.52-6.38, IV B H [CHC(Li)]- 7.3 (CH3)3slGH2G1. 5.96 0-35 3)3SiGH2[CHC(B1O 10)] 42-52 B 47.0 462 46.15

1 Added as 106 ml. of a diethyl ether solution containing 2.1 grams of LBWHMCHG (Li)] 2 Added as 12.7 ml. of diethyl ether solution containing 10.74 grams of B H [CHC( 3 Added as 127 ml. of dlethyl ether solution containing 0.72 grams of B H [CHC(Li)] finally 50 ml. of a clear solution of methyl lithium in di- EXAMPLE V In this example the compound:

[og si/onro:lB H

3.1 grams (0.02 mole) of B H [C(Li)C(Li)] in 56 milliliters of diethyl ether in the same manner as described in Example I (Part B). The starting material, B H [C(Li)C(Li)], was made by the process described and claimed in the above Ager and Heying application Serial No. 809,571. In preparing B H [C(Li)C(Li)] two moles of methyl lithium were reacted with each mole of B H (CHCH) present in the reaction mixture. The course of the reaction was followed as in the preparation of B I-I [CHC(Li)] in Example I, Part A by measuring the evolution of methane with a wet test meter. The product as crystallized from pentane had a melting point of 149150 C. Analysis of this product gave the following results:

Calcd. for c n sia B, 47.4; C, 31.6; H, 8.9. Found: B, 46.8, 46.9; C 32.8, 32.9; H, 9.39, 9.34.

EXAMPLE VI Dimethylchlorosilylcarborane In this example 9.0 grams (0.07 mole) of dimethyldichlorosilane was reacted with 10.5 grams (0.07 mole) of lithium carborane dissolved in diethyl ether in the same apparatus and in the same manner as described in Example I yielding dimethylchlorosilylcarborane 3) zclsi 10 10)] The boron-containing solid materals produced by prac ticing the method of this invention can be employed as ingredients of solid propellant compositions in accordance with general procedures which are well understood in the art inasmuch as the solids produced by practicing the present process are readily oxidized using conventional solid oxidizers such as ammonium perchlorate, potassium perchlorate, sodium perchlorate, ammonium nitrate and the like. In formulating a solid propellant composition employing one of the materials produced in accordance with the present invention, generally from 10 to 35 parts by Weight of boron-containing material and 65 to 90 parts by weight of the oxidizer are used. In the propellant, the oxidizer and the product of the present process are formulated in admixture with each other by finely subdividing each of the materials and thereafter intimately mixing them. The purpose of doing this, as the art is well aware, is to provide proper burning characteristics in the final propellant. In addition to the oxidizer and the oxidizable material, the final propellant can also contain an artificial resin, generally of the urea-formaldehyde or phenol-formaldehyde type. The function of the resin is to give the propellant mechanical strength and at the same time improve its burning characteristics. Thus, in the manufacture of a suitable propellant, proper proportions of finely divided oxidizer and finely divided boron-containing material can be admixed with a high solids content solution of partially condensed urea-formaldehyde or phenolformaldehyde resin, the proportions being such that the amount of resin is about 5 to 10 percent by weight based upon the weight of oxidizer and the boron compound. The ingredients can be thoroughly mixed with simultaneous removal of solvent, and following this the solvent free mixture can be molded into the desired shape as by extrusion. Thereafter, the resin can be cured by resorting to heating at moderate temperatures. For further information concerning the formulation of solid propellant compositions, reference is made to US. Patent 2,622,277 to Bonnell and to US. Patent 2,646,596 to Thomas.

The compound of the formula as described in Example I has the same structural formula as structural Formula I in FIGURE 1 with the exception that the hydrogen atom indicated by the single asterisk is replaced by --Si(CH (C H Si[CHC(B H the compound described in Example III has the same structural formula as structural Formula I in FIGURE 1 with the exception that the 6 hydrogen atom indicated by a single asterisk is replaced by -\SI(C5H5)3.

The compound (CH SiCH [CHC(B I-I1o)] as described in Example IV also has the same structural formula. as structural Formula in FIGURE 1 with the exception that the hydrogen atom designated by a single asterisk is replaced by --CH Si(CH The compound:

CHE-C- B io ro C 11,-0-

as described in Example V has the same structural formula as structural Formula I in FIGURE 1 with the exception that the hydrogen atoms indicated by the single and double asterisk are replaced by the radical:

Si C CHP The compound (CH ClSi[CHC(B H u)] as described in Example VI has the same structural formula as structural Formula I in FIGURE 1 with the exception that the single hydrogen designated by a single asterisk is replaced by -SiCl(CH The compound of the formula as described in Example II has the same structural formula as structural formula H in FIGURE 1.

What is claimed is:

1. A process for the preparation of a silicon-containing organoboron compound which comprises reacting an organoboron alkali metal compound of the formula:

wherein R and R are each selected from the class consisting of hydrogen and an alkyl radical containing from 1 to 5 carbon atoms and wherein R and R are each selected from the class consisting of hydrogen, an alkali metal, and alkyl radical, and an alkenyl radical, at least one of R and R being an alkali metal and the total number of carbon atoms in R and R taken together not exceeding eight with a silane compound of the for mula:

R SiR wherein R is selected from the group consisting of an alkyl radical containing 1 to 5 carbon atoms and an aryl radical containing not more than 10 carbon atoms and wherein R is selected from the group consisting of a halogen and a haloalkyl radical containing from 1 to 5 carbon atoms, said halogen being selected from the group consisting of chlorine, bromine and iodine, and n is an integer of from 1 to 3 with the proviso that when R is a haloalkyl radical n is at least 2.

2. The process of claim 1 wherein the said organoboron alkali metal compound is an organoboron lithium compound.

3. The process of claim 1 wherein the said organoboron alkali metal compound is B H [CHC(Li)].

4. The process of claim 1 wherein the said organoboron alkali metal compound is B H [C(Li)C(Li)].

5. The process of claim 3 wherein the said silane compound is (CH SiCl.

6. The process of claim 3 wherein the said silane compound is (CH SiCl 7. The process of claim 3 wherein the said silane compound is 8. The process of claim 3 wherein the said silane compound is (CH SiCH Cl.

9. The process of claim 3 wherein the said silane compound IS 7 8 10. Silicon-containing organoboranes selected from the wherein R is a bivalent saturated hydrocarbon radical class consisting of: containing 1 to 5 carbon atoms, wherein n is an integer b a from 1 to 3, m is an integer from 0 to 2, r is an integer and )qBmHsRR of from 0 to lsarglHtgi o; m plus 12 is not over 3.

e r V a a)3 l 10 1o Z JI )(2-1) )](2r) 5 12. 3)2 10 10)]2 wherein R and R are each selected from the class con- 13. (C H si CHC(B H sisting of hydrogen and an alkyl radical containing 1 14 (cI-I siCH [CHC(B H to 5 carbon atoms, wherein R is selected from the class 15, consisting of hydrogen, an alkyl radical containing 1 b CH3 to 8 carbon atoms and an alkenyl radical containing 1 to 8 carbon atoms, wherein R is an alkyl radical con :l taining 1 to 5 carbon atoms, wherein X is a halogen on, 0H,0

selected from the class consisting of chlorine, bromine, g

and iodine, wherein R is a haloalkyl radical containing 15 (CH3)2C1S1[CHC(B10H10)]- l to 5 carbon atoms, said halogen being selected from N f d the group consisting of chlorine, bromine and iodine, ore erences cle UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,137,719 June 16, 1964 Stelvio Papetti It is hereby certified that error eppears in the above numbered petent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 21, for "ralical" read radical column 6, line 5 after "Formula" insert I column 8, line 6, for "(CH SiJCHC (B oH read (cH s1[cHc(B a )J Signed and sealed this 3rd day of November 1964,

(SEAL)- Am emss'r w. SWIDER EDWARD J. BRENNER blunting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,137,719 June 16 1964 Stelvio Papetti It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 line 21, for "ralical" read radical column 6, line 5, after "Formula" insert I column 8 line 6, for "(CH SijCHC(B H read Signed and sealed this 3rd day of November 1964.,

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,137,719 June 16 1964 Stelvio Papetti It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 21, for ralical" read radical column 6 line 5, after "Formula" insert I column 8 line 6, for "(014 sijcHc(B H read (CH S1[CHC(B H Signed and sealed this 3rd day of November 1964.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attcsting Officer Commissioner of Patents 

1. A PROCESS FOR THE PREPARATION OF A SILICON-CONTAINING ORGANOBORON COMPOUND WHICH COMPRISES REACTING AN ORGANOBORON ALKALI METAL COMPOUND OF THE FORMULA:
 10. SILICON-CONTAINING ORGANOBORANES SELECTED FROM THE CLASS CONSISTING OF: 